Friction clutch



Nov. i3 i923.,

31,473,626 E. o. HAMREN FRICTI 0N CLUTCH Filed Jan. 29. 1921 4 Sheets-Sham; 1

NOV. 13, i E. O. HAMREN FRICTION CLUTCH Filed Jan. 29, 1921 4 Shees-Shee 2 W 5/ 5032551686 Q7 3 o? f5 f {95 l 33 f 3 72 J0 u f7 Nov. 13l923.

E. o. HAMREN FRIcTIoN CLUTCH Filed Jan. 29 1921 4 Sheets-Shania 3 Patented Nov. i3, lZS.

ERIC O. HAMREALCF CHICAGO, LLINCS.

FRICTIGN CLUTCH.

Application filed January 29, 1921.

To all 'LU/0m t may concern.'

Be it known that I, ERIC @.YHAMREN, a citizen or' the United States, residing at Chicago, in the county ot' Cool; and State of Illinois, have invent-ed certain new and useful Improvements in Friction Clutches, of which the following is a description.

My invention belongs to that general class of devices known as clutches, and relates particularly to a clutch mechanism `wherein power is transmitted from a driving element to a driven element. through suitable fric` tion mechanism which may be controlled at will. The invention has among its objects the production of a device of the kind de-v scribed that is simple, convenient, reliable, eilicient, powerful, compact, durable and satisfactory for use wherever -found appli-` cable. It has particularly as an object the production of a device of the kind described which will operate quickly and easily beth to engage or release without excessive wear ot the parts and which will have high et"- iciency. It has also as an object the production of a clutch mechanism which may be constructed to operate in one direction, or in both directions, depending upon the uses intended. Many other objects and advantages ot the construction herein shown and described will be obvious to those skilled in the art from the disclosure herein given.

-To this end my invention consists in the novel construction, arrangement and combination of parts herein shown and described, andV more particularly pointed outin the claims.

In the drawings, wherein like reference characters indicate like or corresponding Partis Y Figa l is a sectional view taken tially on line `ll of Fig. 2 ot proved mechanism;

Fig. 2 is a sectional view tially on linei2-2 ot Fig, l;

Fig. 3 is a sectional view taken tially on line 3--3 ot. Fig. l;

Fig. 4L is a sectional view taken tially on vline t-t of'Fig. l,

Fig. 5 is a. view taken substantialy on line 55 ot' Fig. 2;

Fig. 6 a detail sectional view;

Figs. T. S and 9 are diagrammatic views illustrating the operation ot the clutch mechanism; Y

F ig. l0 is a sectional view taken substansubstaniny imvtaken substansubstansubstai i- Serial No. 440,975.

tially on line 10-l0 ot F ig. ll, similar to Fig. l, illustrating a slightly modified construction in v-rhich the driving element may be operated in either direction;

F ig.` ll is a sectional view taken substantially on line ll-ll of Fig. l0; and

Fig. l2 is a sectional view taken substantially on line l2l2 ot Fig. ll.

v In the drawings ll have shown only the preferred embodiment of the invention, two types being illustrated. Referring iirst to Figs. l to 8, inclusive, l represents a shaft or the equivalent, which may be termed the drix'fing member, and 9; a part which may be termed the driven member, which in the construction shown is provided with they teeth 3, and constitutes a gear, but which may be made in the form ot a gear, sprocket, pulley, sheave or any equivalent for the purpose. UWhile under ordinary circumstances either one may represent the driving element, it is preferred to have the shaft l as the driving element, the same rotating in the direction indicated by the arrow in Fig. 2. riChe driven member or part 2 is mounted on a part 4, which` is preferably secured to the shaft by a key 4: or any equivalent means ttor the purpose, 5 being a bearing member or renewable bushing which may be arranged as shown, it so desired. The driven member 2 is preferably extended as at 6 and recessed so as to 'form a chamber or casing, the inner `tace 7 being preterably constructed to cooperate with the triction member or element lereinatter described. The open end of the extending part 6 is normally closed by a plate S, or equivalent inea-ns i'or vthe purpose, secured in place by screws 9 or the lile, 9 being a packing of suitable material. in the construction sliown, the plate not only maintains the driven men'iber in operative relation withtlie other parts o t the mechanism. but also serves as a retainer tor retaining oil or lubricant which may perhaps be sui plied to the clutch. it is ixnn'iaterial, how

ever, Yin so tar as the 'present invention isccuicerned, as to whether a lubricant or any other liquid or fluid is inserted in the eas' ig ifor any purpose whatever. The member t is preferably extended within the casing. as indicated at l2, the same having outwardly extending portions lb carried by the parts 14, and an ertending part l5 which carries a stud or pin 16, which supports a yolre or comparatively easy.

posite end which is anchored onto the portion 1T, or secured thereto. by screwsl or equivalent means for the purpose. As most clearly shown in Fig. 3, portion 17 is eut away as indicated at so that only a small portion ofthe member or ring 19- 1s prevented from having'l free plav when 'expanded or contracted. Normally, the tendency of the ring is to contract away from the inner face 7 of part (i so. that the parts are out of engagement and there is no transmission bet-Ween the shaft 1 and. the part 2. The part 18 carries a pin 25 upon which are mounted rollers or friction-element cooperating' members 26. I also preli'er to provide one` or more pins 27 and Q9 on the yoke 17e-lndlich carry rollers 28 and 30 or the equivalent also arranged to cooperate with the friction element 19, as will be described in the operation of the device.

Referring` to Figs. 1 and 2, 31 member mounted on the shaft 1, and which rota-tes therewith through its interconnection with the member 17-`18, in a manner hereinafter described, but which may be moved longitudinally of the shaft. The saine may be formed as indicated at 32 for engagement with a shift lever or any equivale-nt mechanis'm provided for operating the same. The member 31 extends inwardlyv through the plate 8 and into the chamber in part (i, and is formed with the projecting ribs 33 or the equivalent. :is most clearly shownin 1 and 6, the vribs B3. are arranged on an augrle or inclined so that the same sul'istautially constitute cai-ns having cam faces adai'ited to cooperate with suitable faces on the men1- ber '17-18. Member 1T-18 is formed with. faces and With.- projecting parts il? having faces 36. The faces 35 and 3G are spaced :L sufiicient distance apart, as indicatedY atv 341 in 3, so that the ribs can project bct-Ween the-faces on the member llfumlS. Tl: Will be` particularly noted by referring to the drawings that the several tacos are so designed as to give substantially a point contact, thereby making shifting of the parts Obviously, as the member 31 is moved in or out the ribs cooperating ivith the member lil-1S spread the ends ofthe same or move them together, as the case may be.

As was before mentioned, the friction elcment or ring 19 in the construction described, is secured. to the member 17. l." have also illustrated the opposite end of the friction element loosely securedto. the portion 1Sz so that as member 18v sliirings or moves back to its inoperative position, `it will cooperate or controlthe end of the frition element and positively break its engagement with the driven member. VIn the preferred construction, spring 38 is arranged at the extreme end 20 of the friction element and secured thereto by means of rivets 39 or any equivalents forthe purpose. The part 3S is constructed to enga-ge With the rollers 26.

The type of clutch mechanism described is intended to drive in one direction only, as-

ordinarily this is all that is necessary. The d operation of the clutch may be briefly described t'ollows: W lien theV member 231 in itsout positionas indicated in Fig. 1, the friction element v-:illl be out of engagement with the driven clement at face i", but the tivo members 31 and 12 will be driven to- Ic'etlier, because the member 12 is splined to, the shaft, driving the member 31 through the cams 33 and 3T. The parts guide or center the friction rin;- when out of operative drivii'igv position. This being the cas l, member a-, parts llS and iiction element, part- 19, rotate freely Within part (i, Withoutdriving part VGf and the driven element 2. When part 31 is pushed inef'ardl'y, the same tends to. expand orr separate the disconnected ends of part 113-18, at pin 1G. The pin therefore is moved relatively of the separated ends of the yoke a slight distance and rcengages one of the arcuate faces ot the parts ring' into engagement with the face.v 7', that is expands the ring into engagement with fare 7, rocking the yoke men-iber on the pivot 16. As part 17-18 is substantially rocked on its pivot 16, due to the'rotatingf` element.engaggingi the relatively stationary element 2, rolls 28 and 30 also cooperate with the friction element, tending to. expand and' force the saine into engagement with the driven element. Obvioust/v assoon as the end 2O engages the face IQthe entire ring engages and becomes operative. The positive expansion at the three points causes a multiplying oit' the poiveigivhich maybe t'ansmitted Without slippage, and the pres sure is maintained until the clutch is released. lllhen member is Withdrawn, releasing the clutch action, part 17e-1S moves and releases the pressure. It will be noted that the end Q0 of the friction element is quickly disengaged from the. face 7, the disengagement being almost instantaneous about the entire friction element. The clutch parts substantially' engage and disengage Without slip-page between the` friction faces,- this being particularly true with the disengaging. Some slippage during the engaging' of course prevents shock; and; jar

3T (the left hand face shown in Fig. Y 2). .Roller 26, tends to; .force the friet-ioni ilfl l .Ill

and strain on the parts. rllhere is, however, no slippage against pressure during the releasing of the clutch. It will be particularly noted that the clutch is substantially selfadjusting. That is to say, is so constructed that wearing of the parts does not throw the same out of adjustment or require a readjustment. It may be mentioned. that l have not shown the friction ring 19 provided with a lining, nor have l shown any kind of a lining or facing for theV cooperating part 6. Such facing or lining, however, is well known in the art, and it is not considered necessary toV describe the same in detail herein, no1I the method of applying the same should it be found desirable to use it.

In Figs. 7, 8 and 9 of the crawings there is shown diagrammatically the working action of the clutch. Fig. 7 shows the ring 19 disengaged. lVhen the member 31 is moved in, the yoke member' is spread to first engage the driving and driven members at the point 26, swinging the yoke and split ring about the pivot 16, as shown in dotted lines in F ig. 8 and in full lines in Fig. 9, the ring also engaging the driven member at the points 28 and 29. The release or withdrawal of the member 31 from its spreading of the yoke will cause the yoke and ring to pivot about the point 16 in the reverse direction to positively pull the ring away from the driven member to stop the rotation of said driven member.

In Figs. 10, 11 and, 12 there is shown a. clutch arranged tov drive the driven element in either direction, depending upon the direction of the rotation of the driving shaft L1:1. Referring to the figures mentioned, y-ll represents a driving shaft or the like, and e2 a driven element of the desired type, that is, the same may be a gear as shown, or a sprocket, gear, pulley or the equivalent. Arranged on the shaft and suitably secured thereto is the member la corresponding to part 4 previously described, the same being provided with the part 45, to which part 42 may be keyed or otherwise secured thereto, as indicated at 45, and which is provided with an extending casing part -lG constructed with the friction face et?. 4.6 represents the end plate secured in place by screws 419,

it being understood that this may be made as desired. The part ll is pro-vided with the parts 52, and 551. similar to those previously described in the other construction, and also carries the pin 55. Loot-ely carried by the pin is the yoke member 56 carrying the pins 58 substantially similar lo the pins described in the other construction. Arranged within the casing is the friction element or ring 59, 60V and 60 representing the ends of the same. With this particular construction, the friction ring is not secured at either end or at all to the member 56, but

is substantially loosely arranged within the casing, although caused to rotate with the driving element. As shown, the part 56 is provided with the extending lugs 61 arranged to form a stop or abutment for either end of the friction element. ln this construction, as in the other, there is provided the controlling member 68 having the ribs 62 for controlling the yoke member 56. l have shown the friction element or ring provided with members 6i arranged to engage brackets 65 on the part 56, the same being so arranged that it will positively cause the disengagement of the friction ring with the friction face 47 when the clutch is released. 1When the driving member is driven in either direction, the throwing in of the cams will cause the member 56 to expand at its ends, and, dependent upon which direction the shaft is driven, the member 56 will engage a free end of the spring ring 59 to expand it into friction driving Contact with the member 46.

- lVith this double acting or reversible driving construction, stop 6l engages the end 60 of the friction ring and substantially anchors that end, .the other end being the free end. Referring to Figs. 10 to 12, when the drivingmember is driven in the direction indicated by the arrow in Fig, 11, then end 60 will be substantially the free end of the spring and end 60 will abut against the stop. Obviously when yoke member 56 is expanded as described, the friction ring will be expanded into engagement with the driven element, causing that to be driven, thereby transmitting powe' as dcsired. Upon releasing the clutch mechanism by moving member 63 outwardly, thc clutch mechanism will become inoperative, and in this connection it will be noted that the friction ring is pulled away from the friction face and substantially releases as previously described. lf the driving member is driven in the opposite direction, the result will be the same. The prongs or parts 65, arranged to cooperate with the cooperating members 6l, may be extended sufficiently to be in engagement with the members (it at all times if desired, so that a connection is formed between the carrier and the friction member to prevent thc latter being thrown. out by the centrifugal force and thereby preventing its contacting with the friction facev and dragging over the same.

The basic working principle of thc clutch, when being engaged or brought into operation as follows Assume that the loose end of the friction band 19 is at the right side of the axis as shown (Figs. 2 and 3). the tight end bcing on the left side. The clutching movement (sliding the sleeve 31 to the left) forces the free end 18 of the carrier or yoke against the loose' end 20 of the band, which in turn is pressed against the drum or flange. ssuming that the shaft l rotates the drum in a clockwise direction, it will be seen that the drum tends to take the loose end of the band with it, due to friction therebetween,

l for friction in band-brakes. The tight end of the band is fixed to the carrier, which in turn is. pivoted about the pin l5. The pressure from the tight end, therefore7 acts on the carrier7 which in turn pivots and reacts against the band and drum with a pressure proportional to the radial distance from the tight end of the band to. the ,pivot of the carrier. To sum up, it is apparent that the pressure or friction at the tight end is, utilised to further increase its own friction.

It will be noted that with all of the constructions described herein, the pressure is substantially completely released between the carrier and the friction ring before the friction ring is brought back to its disengagel position. The first movement of the members 3l or (33 to release the clutch mechanism immediately relieves all pressure of the lex'n,

ble and substantially floating carrier on the friction ring, thereby securing the effects previously described. It should be under stood that I have only shown the preferred embodiment of my invention and that the yoke and friction element may be varied7 a yoke made up of several links suitably secured together affording substantially the same effect as the one-piece yoke shown, and in this case instead of a one-piece ring` or friction element, this may be made in seg-V ments or shoes carried by the yoke, affording the same effect as the construction illustrated. It may be also mentioned that I have set forth andv particularly described the mechanism as adapted for a clutch for transmitting power, but obviously where one of the mem 1ers corresponding to either the drivingor driven member is stationary, the device makes a very satisfactory frictionbrakc. The device is therefore adapted not only to transmit motion.y but also, if desired. to be employed for preventing the trans mission of motion.

Having thus described my invention. it is obvious that various immaterial modifb cations may be made in the same without departing from the spirit of my invent-ion; hence I do not wish to be understood as limiting myself to the exact form, construction, arrangement and combination of parte herein shown and described, or uses mentinted,

saine at a. plurality of'spaced points, and

operating means for rocking said expander. Q. A plurality of elements and mecha-msm for operatively connecting the saine whereby one may be driven-by the other, said mechanism comprising a friction member arranged to engage oneV of saidelements, a resilient ex'- pander yoke therefor loosely carried by one of said elements and arranged -to carry and engage the friction mengibe'r at a plurality of points, and Ymeans Vfor controlling said en pandcr. f y

3. fr plurality of movable elements and mechanism for operatively connecting the saine whereby one may be driven by the other, said mechanjisn'i comprising a friction ring, a resilient expander'therefor pivotally arranged on an axis parallel to and to one sido of the rotational axis of the driving element to support the ring and operatively connect it to one of said elements and operaT tively engage the same at a plurality of points and enpandit into driving engage ment with the other of said elements, and means for controlling said expander.

ll. In a device of the kind described and in combination, a rotatable driving element7 a rotatable driven element, and means for operatively connecting the same, comprising a friction ring arranged to. operatively engage one element, and resilient-means substantially loosely carried'by the other cle ment at a point Vat one side of its axis of rotation for arrying said friction ring and expanding said ring and maintaining' the same in engagement with the other element through its length. Y

5. ln a device of the kind described Vand in combinationv` a rotatable driving element, a rotatable driven clemenigand means for operatively connecting the saine, comprising a friction ring arranged to operatively engage one clement. and resilient expansible means substantially loosely carried by the other clement at a point at one side of its i artis of rotation for carrying and expanding said ring and maintaining the same in engagement `with the other element thrmigh its length or positively disengaging the ring from said clement.

Y 6, In a device of the kind described, and in combination, a driving element, 'a driven element and means for operatively connecting the same, conniirising a friction ring ar ranged to engage one of saidelements,a re silient yoked carrier for said friction ring pivotally Carried by the other element at a point outside the axis of rotation thereof and operable to engage the ring at a plurality of points intermediate its ends, and means for controlling said carrier to pivot it on said offset pivotal axis, whereby the friction ring is brought into engagementwith one of said first mentioned elements at a plurality of points. Y l

i. In a device of the'kind described and in combination, a driving member, a driven member journaled on said driving member, and means for transmitting' rot-ary movement therebetween, comprising a resilient. split ring between said members and arranged to frictionally engage one of them, and a resilient expansible carrier for expanding said ring at a plurality of points,

and pivotally carried by one of said members at one side of its driving axis, and means for actuating` said carrier to control the expansion or contraction thereot` and of said ring, said last mentioned means being mounted on the same member as said carrier.

8, In a device'of the character described and in combination, a driving member, a driven member journaled on said driving membe and having a flange surrounding it, and means for transmitting` rotary movement therebetween, said means comprising a resilient split ring adapted to be moved into frictional contact with said driven member, a carrier for said split ring pivotally mount ed on said driving member at a point offset from its rotational axis, rollers on said carrier adapted to engage and control the expansion or contraction of said ring, and means for actuating said carrier, said means comprising a member loosely mounted on the driving shaft and operable to engage said carrier.

9. In adevice of the kind described and in combina-tion, a driving member, al driven member journaled thereon, and means forl transmitting rotary movement therebetween, said means comprising a yoke-shaped resilient split carrier member straddlingl the driving member and pivotally carried thereby, said pivotal axis being offset from and parallel to the rotational axis of said driving member, an expansible friction element carried by said carrier member, a plurality of bearing rollers on said carrier adapted to engage said expansible friction element at a plurality of points, said carrier having a cam-way therein, and a cam carried by the driving member and operable to engage said cam-way to expand or contract said carrier, whereby the expansible friction element is moved into or out of engagement with said drivenmernber.

10. In a device of the kind described and in combination, a driving member mounted upon a shaft, a driven member journaled on Y said driving member, and means for transmitting rotary movement therebetween,

said means comprising a resilient split ring adapted to be expanded into contact with said driven member, a resilient split carrier secured to said ring, said carrier being pivotally mounted eccentrically of said drive shaft, a pair of parallel spaced lugs and recesses on said carrier, and actuating means for controlling the expansion or contraction of said carrier, said actuating means being freely mounted on said shaft and having spaced ribs engageable in said recesses to expand or contract said carrier and ring.

11. In a device of the kind described and in combination, a driving member mounted upon a shaft, a driven member journaled on said driving member, and means for transmitting rotary movement therebetween, said means comprising a resiliently expansible friction ring, a carrier for said resilient ring, saidcarrier straddling said shaft'and comprising a one-piece split yoke, one of the split ends being secured to one end of said ring, a pin secured to said driving member and pivotally mounted in said carrier, said pin being spaced radially from tle rotational axis of said shaft, each of said split ends of the carrier having a recess therein, a collar freely movable on said shaft and having a pair of mutually divergent cam projections, whereby when said collar is moved in one direction alongthe shaft, said projections will engage in said grooves on the carrier to expand the carrier and ring and transmit drive between s'aid driving and driven members, and when the collar is moved longitudinally of the shaft in the opposite direction, it will contract said carrier and ring and disengage said driving and driven members.

12. In a device of the kind described andV in combination, a drive shaft, a driving member rotatively carried thereby, a driven member journaledupon said driving member and having a flange surrounding the same, and means for transmitting rotary movement between said driving and driven members, said means comprising a resilient expansible split ring arranged within said flange, a resiliently expansible carrier for said split ring, said carrier having split ends and being pivotally mounted on said driving shaft on an axis offset from the rotational axis thereof, rollers carried by said carrier and engageable with said ring at a plurality of circumferentially spaced points, a spider for limiting the inward contractile movement of said split ring, a collar slidable longitudinally of the shaft, and means for controlling the expansible and contractile movement of said carrier, said means comprising cam-ways at the split ends of'said carrier and mutually divergent longitudinally extending cams on said collar and engageable in said cam-ways, whereby 1novement of the collar in one direction will exsubstantially pand the carrier, moving the rollers against the ring, whereby the ring will be in contact with the driven member substantially throughout its length, and movement in the opposite direction upon said shaft will release said drive.

13.V In a device of the kind described and in coi'i'ibination, a drive shaft, a driving member secured thereto, a driven member' journaled on said driving member, and means for transmitting rotary movement between said driving and driven members,

`Said means comprising a resilient split ring engageable with said driven member, a resilient split carrier tor said ring, said carrier being substantially U-shaped and straddling said drive shaft and having recesses at its ends to lorm a pivotal bearing, a pin on said driving member and pivotally engageable in said recesses to carry the carrier, the axis oit said pin being radially spaced from said drive axis, a plurality of circumferentially spaced rollers on said carrier and adapted to engage said ring, a. camivay on said carrier and a cooperating cam slidably carried by said shaft and engageable with said cam-way on the carrier to ex-l pand or contract the same, whereby the rollers carried thereby are moved into or out or' engagement with said ring to force the same into or out of engagement With the driven member, and a member at the free end ot' the ring for releasing` the ring -from the driven member when the carrier is contracted, said member comprising a resilient strip on said ring and engageable ivith the inner side of one ot' said rollers.

14. In a mechanism of the kind described and in combination, a driving shal't. a driving member secured thereto, a driven member journaled on said driving member and having a flange surrounding the same, and

means tor transmittingl rotary i'i'ioven'ient be` tvveen said driving and driven members` said means comprising a. split expansion ring concentrically within said flange, a carrier tor said ring. said carrier comprising a yoked expansible member straddling said drive shaft, one end o said ring being secured to one ot said yoke legs, a series ot rollers arranged on said carrier and circumferentially SpaCedivithin said ring, the ends of said yoke being recessed to provide a bearing, a pivot pin journaled in said recess and secured to saidr driving member, `the axis or' said pivot pin being spaced radially from the rotational axis of the driving member, means for expanding and contracting said carrier whereby the rollers will be engaged with and disengaged :from said ring, and means for disengaging the free end of said ring from the driven member upon contraction 4o'l the carrier, said last mentioned means comprising a spring arranged at the extreme end of the ring and vieldingly engageable with one ci the rollers in contact with said ring, Where by when the carrier is contracted the roller engageable with said spring Will actuate said spring and positively break the engagement ot the ring and driven member.

l5. In a device of the Vkind described and Vin combination, a drive shaft', a driving sleeve secured thereto, a driven member journaled on said sleeve, said driven member having a casing surrounding said sleeve, and means for transmitting rotary movement betvveeu said shaft and driven member, said .means comprising a resilient split ring arranged within said casing, a pivot pin carried by said driving sleeve, a U-sliaped carrier pivotally 'mounted onsaid pinv'ithin said casing, said carrier straddling said shaft and pivotally mounted at'its open ends on said pivot pin, the axis of said pivotal mounting being parallel to and spaced from the rotational axis of said shaft, meansfor limiting the inward contractile movement of said ring, said means lcomprising spider arms on said sleeve Whose arms terminate adjacent said ring, one end oi said ring being secured to one end of said carrier, a plu- 'ality ot rollers carried by said carrier and engageable with said ring and spaced circumferentially thereof, said carrier having a pair of recesses at its ends and extending longitudinally of the pivot pin, a collar vfreely journaled on the shatt and slidable longitudinally thereof, said collar having a pair of npstanding ribs thereon mutually divergent for a portion of their length and parallel near their convergent ends, the spacing of said ribs at their parallel portions being substantially equal to the normal spacing of said recesses in thecarrier, Whereby said collar may be moved longitudinally of said shaft and the convergent' ribs Will eng'age in the recesses of the carrier to positively expand the carrier so that the rollers carried thereby Will be moved outwardly and vmsiti'vely expand the ring carried by said carrier into engagement with the driven member. Y

1G. In a device of the kind described and in combination, a drive shaft, a driving sleeve secured thereto, a driven member journaled on said sleeve, said driven member having a casing surrounding said sleeve, and means tor transmitting rotary movement between said shaft and driven member, said mea-ns comprising a resilient split ring arranged Within said casing, a pivot pin carried by said driving sleeve, a U- shaped vcarrier Within `said casing, straddling said shaft and pivotally mounted 'at its open ends on said pin, the axis of said pivotal mounting` being parallel to and spaced from the rotational 'axis of said sha't't, means for limiting the inward contractile movement: ot' said ring, said means comprising spider arms on said sleeve whose arms terminate adjacent said ring, one end of said ring being secured to one end of said carrier, a plurality of rollers carried by said carrier and engageable with said ring and spaced cireumferentially thereof, said rarrier having a pair of recesses at its ends and extending longitudinally of the pivot pin, a collar freely journaled on the shaft and slidable longitudinally thereof, said collar having` a pair of upstanding ribs thereon mutually divergent for a portion of their length and parallel near their convergent ends, the spacing of said ribs at their parallel portions being substantially equal to the normal spacing of said recesses in the carrier, whereby said collar may be moved longitudinally of said shaft and the convergent ribs will engage in the recesses of the carrier to positively expand the carrier so that the rollers carried thereby Will be moved outwardly and positively expand the ring carried by said carrier into enga-gement with the driven member, one of said rollers being mounted adjacent the free end of said ring, and means cooperating With said roller to positively break the engagement of the ring with the driven member when the carrier is contracted, said mea-ns comprising a spring secured at the free end of said ring and inwardly bent so as to yieldingly contact With said roller.

17. In a device of the kind described and in combination, a rotatable driving element, a rotatably driven element, and means for operatively connecting the same comprising a. friction ring arranged to operatively engage one element and resilient carrier means substantially pivotally carried by the other element at a. point to one side of its axis of rotation for carrying said friction ring, and means for rocking said carrier to expand it to control said ring.

1S. A plurality of elements and mechanism for operatively connecting the same, whereby one may be driven by the other, said mechanism comprising a friction member arranged to engage one of said elements, a resilient expander yoke therefor pivotally carried by one of said elements on an axis parallel to the rotational axis of said elements at one side thereof and arranged to carry and engage the friction member at a plurality of points, and means for rocking said yoke on its pivotal axis for controlling said friction member.

19. In a device of the kind described and in combination, a driving shaft, a driven element, a drum journalled on said shaft, and means for operatively connecting said driving and driven elements, comprising a split, resilient band adapted to frictionally engage said drum, a split resilient yoke straddling the shaft and supportingly engaging said band at a plurality of circumferentially spaced points, said yoke having one end fixed to one end of said band, and the other end slidably engageable therewith, and a pin carried by said shaft and offset from the rotational axis thereof, and pivotally carrying said yoke.

ln testimony whereof, I have hereunto signed my name-in the presence of tivo subscribing Witnesses.

ERIC O. HAMREN.

Witnesses:

ROY W. HILL, BERTHA HARTMANN. 

